Field
This invention relates to a medical prosthesis and, more particularly, to a graft prosthesis for placement within a corporal lumen, such as the lumen of a blood vessel or artery.
State of the Art
Various fluid conducting body lumens, such as veins and arteries, may deteriorate or suffer trauma so that repair is necessary. For example, various types of aneurysms of other deteriorative diseases may affect the ability of the lumen to conduct fluids and in turn may be life-threatening. In some cases, the damaged lumen is repairable only with the use of prosthesis such as an artificial vessel or graft.
For repair of vital vessels such as the aorta, surgical repair is significantly life-threatening. Surgical techniques employed involve major surgery in which an artificial section of vessel is spliced into the diseased or obstructed lumen. That is, the damaged or diseased portion of the lumen may be surgically removed or bypassed and an artificial or donor graft inserted and stitched to the ends of the vessel which were created by the removal of the diseased portion. Kaj Johansen, Aneurysms, Scientific American, 247:110-125, July 1982. A variation of the typical suturing technique is described by Albert W. Krause, et al., Early Experience with Intraluminal Graft Prosthesis, American Journal of Surgery, 145:619-622, May 1982. The device illustrated in U.S. Pat. No. 3,908,662 to Razgulov, et al. is an example of a device to be used in such a surgical procedure.
Other devices for the repair of lumens or vessels such as veins arteries include a nitinol coil with a graft. The nitinol coil is reduced in dimension when cool. When placed in the body its temperature increases, and it returns to a preselected dimension to hold a graft within the lumens of the vessel. Such devices are discussed in detail in Charles T. Dottner, et al., Transluminal Expandable Nitinol Coil Stent Grafting: Preliminary Report, Radiology 147:259-260, April 1983, and Andrew Cragg, et al., Nonsurgical Placement of Arterial Endoprostheses: A new Technique Using Nitinol Wire, Radiology 147:261-263, April 1983. The use of devices such as the previously discussed nitinol wire may not be desirable due to the danger of penetrating and damaging the vessel""s wall during the emplacement process.
U.S. Pat. No. 4,140,126 To Choudhury discloses a device for intraluminal repair of an aneurysm. This device is positioned in a vessel in a collapsed form and then hooked into the vessel with hooks that are mechanically extended by the user. This device is mechanically complex and in turn is susceptible to mechanical failure.
Other intraluminal devices are known, for uses other than the repair of a diseased lumen or vessel. U.S. Pat. No. 3,874,388 to King, et al. discloses a system for closing off a septal defect or shunt in the intravascular system in the myocardial area. U.S. Pat. No. 3,334,629 to Cohn discloses a device for restricting the flow of blood. U.S. Pat. No. 4,056,854 to Boretus, et al. teaches construction and placement of an artificial aortic heart valve. U.S. Pat. No. 3,834,394 to Hunter et al. teaches construction of an intraluminal device to occlude a blood vessel. U.S. Pat. No. 3,540,431 to Mobin-Uddin teaches construction of an umbrella-like filter for intraluminal use. MEDI-TECH, Inc. of Watertown, Mass. sells a device known as the GREENFIELD Vena Cava filter for intraluminal placement. U.S. Pat. No. 3,938,528 discloses a device that is implanted into the vas-deferens or similar lumen for the splicing of the lumen parts.
None of the devices noted above disclose a reliable and quick means or method to repair a vessel intraluminally.
An artificial intraluminal prosthesis for placement in a fluid conducting corporeal lumen has a hollow graft of preselected cross-section and length. The proximal end of the graft is placed upstream within the lumen. The graft is deformable to conform substantially to the interior surface of the lumen. Staples are attached to the proximal end and preferably to the distal end of the graft for stapling the graft to the wall of the lumen.
Each staple has wall engaging members. The wall engaging members of the proximal staple are generally angulated in a downstream direction and have tips for engaging the vessel wall. The wall engaging members of the distal staple are angulated in a direction generally perpendicular to the longitudinal or central axis of the graft, and also have tips for engaging the wall.
Generally, the staples are formed into a V-shaped lattice or framework. In an alternative embodiment, the staples"" framework is U-shaped or sinusoidal. The frame of the staples allows for radial deformation resulting in a spring-like effect when a compressed staple is allowed to expand within a vessel and to sustain itself in that expanded condition.
Preferably, the graft is made of a material suitable for permanent placement in the body such as nylon or dacron. Prior to emplacement, the graft is formed to be substantially cylindrical in shape and formed to have a plurality of substantially evenly placed circumferential bifolds along the length thereof. An optional radio-opaque seam on the exterior of the graft may run along the longitudinal axis of the graft in order for the user to observe graft placement through fluoroscopy or by x-ray.
The system for intraluminally engrafting the hollow graft has placement means for emplacing the graft into the lumen and positioning it at a preselected position. The placement means includes a capsule shaped and sized for positioning within the lumen. A hollow tube extends from the capsule to exterior the vessel for manipulation by the user. The graft is retained with the capsule for positioning the graft in the lumen. The placement means includes operation means for removing the graft from the capsule and for subsequently urging the staples into the wall of the lumen.
Preferably, the operation means includes a catheter slidably positioned within the hollow tube to extend from the capsule to exterior to lumen. The catheter desirably has an inflatable membrane operable by means for inflating the deflating the membrane. Pusher means is attached to the catheter and sized for passing through the capsule and for urging the hollow graft with attached staples out of the capsule through an upstream or front end aperture.
After the proximal portion of the graft is removed from the capsule, the inflatable membrane is desirably moved to within the circumference of the proximal staple and inflated to urge wall engaging members of the proximal staple into the wall.
The balloon is then deflated, and the replacement means manipulated to remove the remainder of the graft from the capsule, thus exposing the distal staple. Preferably, the distal staple is placed and affixed in a manner similar to the proximal staple.
The placement means is then removed from the lumen.